1. Technical Field
The present invention relates to a liquid ejecting head including a piezoelectric element that causes a change in pressure in a pressure-generating chamber communicating with a nozzle opening and has a piezoelectric layer and electrodes for applying a pressure to the piezoelectric layer, and relates to a liquid ejecting apparatus and a piezoelectric element.
2. Related Art
In some of piezoelectric actuators used in liquid ejecting heads, a piezoelectric element having a structure in which a piezoelectric layer made of a piezoelectric material, for example, a crystallized dielectric material, exhibiting an electromechanical conversion function is disposed between two electrodes is used. A typical example of the liquid ejecting head is an ink jet recording head in which a diaphragm configures a part of a pressure-generating chamber communicating with a nozzle opening for discharging ink droplets and a pressure is applied to the ink in the pressure-generating chamber by deforming the diaphragm by a piezoelectric element to discharge the ink as droplets from the nozzle opening.
The piezoelectric material used as the piezoelectric layer (piezoelectric ceramic) configuring such a piezoelectric element is required to have a high piezoelectric property, and typical examples of such piezoelectric material include lead zirconate titanate (PZT) (see JP-A-2001-223404).
However, from the viewpoint of an environmental problem, there is a demand for a piezoelectric material having a less content of lead. As an example of the piezoelectric material not containing lead, BiFeO3 having a perovskite structure shown by ABO3 is known, but the BiFeO3 system piezoelectric material has low insulation and, therefore, has a problem of easily causing a leakage current. Accordingly, there is a problem that it is difficult to apply the material to liquid ejecting heads. In addition, the amount of deflection is small, compared to that of PZT. Accordingly, there is a demand for a piezoelectric material giving a large amount of deflection and having an excellent piezoelectric property.
These problems are not only of ink jet recording heads, of cause, but also of other liquid ejecting heads for discharging droplets other than ink. In addition, these problems are of piezoelectric elements that are used for devices other than liquid ejecting heads.